Flight 5: Stalls & Spins |
Saturday, April 29th. The day is bright and
clear, a good day for flying. It would be, wouldn't it? Have to admit I
haven't been looking forward to this flight; an introduction to stalls &
spins. It all stems from a bad experience I had as a child of 12 or 13 on
a fairground ride. I'll spare you the gory details of my projectile vomiting,
suffice to say there's nothing quite like the humiliation of having to have
the floor under your seat hosed down after you disembark the ride. Well,
I did scream at the rather surly operator several times, "STOP THE
RIDE I'M GOING TO BE SICK!!!", so he can't say I didn't warn him. Anyway,
in spite of the fact that I've never been sick at a fairground since - and
I've been on far more violent and stomach churning rides than that one -
I still have this silly little fear that anything more than straight and
level flight will make me suddenly and rather unpleasantly ill. Worse case
scenario: I spend the rest of the day apologising to my instructor for spewing
all over him. |
I suppose a quick word on stalls would be appropriate here. Contrary to
what my co-workers thought when I told them my next lesson was stalling,
this does not refer to the engine. Yes, when you stall your car the engine
quits, but stalling an airplane is an entirely different matter. A stall
in an airplane is when the wing exceeds the critical angle of attack at
which point the airflow can no longer flow smoothly over the top of the
wing and loss of lift occurs. In layman's terms, you tried to make the airplane
do something it simply refuses to do and you may well pay a price for it.
Depending on the situation (and the type of aircraft), this could be either
a very minor price in which case you just need to unstall the airplane and
carry on about your business, or it could be entirely more serious and something
you may not walk away from. Either way, recognising a stall, what causes
it and how to get out of it (or better yet, avoid it in the first place)
is a valuable part of learning to fly. |
I arrive at the airfield a bit early and Tony and I sit down in the clubhouse
for a pre-flight briefing. This doesn't do much to alleviate my nervousness
as I figure anything that requires a pre-flight briefing must be fairly
serious. Tony gives me the lowdown on what maneuvers we'll be doing and
what kind of response to expect from the airplane. The first thing we'll
be doing is a power off stall recovery in the clean configuration (flaps
up), or a non-standard stall recovery as it is known. Well that doesn't
sound too bad. Next will be the "power on" standard stall recovery
in the clean configuration. Here we may encounter a wing drop due to "tip
stall", which is when the wingtips stall before the wing nearer the
fuselage because the prop wash is still providing some lift. Then it's stalls
with power on and flaps down. This, I'm warned, is when the wing will really
drop with a vengeance. "So is it a fairly violent maneuver?",
I ask. "Depends", says Tony with a grin. "How violent do
you want it to be?". Oh joy. |
We trundle off to the Cessna 152 - G-BHRB again - and after the usual
checks and radio calls we're airborne. We climb to 3400 feet as this
will be the height we'll be stalling from in order to have sufficient
height to recover by 3000 feet. Tony goes through the pre-aerobatic
"HASELL" checklist with me:
- Height - Sufficient to recover by 3000 feet.
- Airframe - Flaps & landing gear as desired, brakes off, in trim.
- Security - Hatches & harnesses secured, no loose objects in cockpit,
gyros caged if necessary.
- Engine - Instruments in green, fuel sufficient, mixture & carb
heat set.
- Location - Away from controlled airspace, built up areas and other
aircraft. VFR (Visual Flight Rules) conditions.
- Lookout - A quick 180° turn to check the area around & below
us is clear.
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Here we go. Tony Hancock's voice from "The Blood Donor" pops
into my head: "Well, this is it, over the top". Tony demonstrates
the power off stall recovery in the clean configuration. He closes the throttle
and hauls back on the control column. With the nose high in the air I can
hear the stall warning buzzing in my ears and feel the buffeting from the
disturbed airflow over the tail surfaces. I wait for my stomach to leap
into my throat in protest as the airplane drops out from under us. And I
wait. I glance at the rate of climb indicator and notice we're dropping
at about 1000 feet a minute. Tony lowers the nose and we recover from the
stall. Power back on and we climb back to 3400 feet. That was it?! We completely
stalled and I didn't even notice it!! Cripes, that was a piece of cake!
Tony demonstrates one more time and then it's my turn. Power off and then
I haul back on the control column. It takes quite a bit of effort to bring
it all the way back and I realise you've really got to want to stall this
thing. I centralise the controls and after the plane recovers I add power
again. Seems pretty straight forward. |
Next is the power on stall. Tony sets the throttle for about 1700 rpm
and then brings the nose up as before. The stall warning goes off and the
left wing drops a bit, right on cue. Tony lowers the nose and crams on full
throttle with a bit of right rudder to correct the yaw. We've only lost
about 50 feet in height. Cool. So far so good. I try the maneuver next.
I should interject at this point and mention something about tip stall that
I'd learned from our pre-flight briefing. Correcting a wing drop in the
usual manner - with aileron - during a tip stall will not work. In fact
it could even make matters worse! The reason being that normally the aileron
on the dropping wing would deflect downwards to raise the wing but as the
stall approaches the lowered aileron may cause the wing to exceed the critical
angle of attack and, instead of rising, the loss of lift would cause the
wing to drop further. At this point you could be on your way to getting
into a full blown spin. So the idea is to correct any wing drop during a
stall with opposite rudder and leave the ailerons neutral. That's the idea,
anyway. In practice I discovered it's not so easy to tell your brain to
leave the ailerons alone, because when that wing drops my natural reaction
is to steer the other way with my hands, not my feet. |
Now the real fun begins; stalls with flaps down. Again, I get a demo first.
30° of flap - the landing configuration, 1700 rpm, nose up, stall warning
goes off and... wham!! , I'm looking out the left window straight down!
Holy shit, he wasn't kidding about that wing drop! One minute I'm looking
up at the sky, a millisecond later the aircraft has rotated 90° on to
its left side!! Yikes!!! It's at this point that it suddenly occurs to me
that, rather than being sick to my stomach as I expected, I'm actually enjoying
it. In fact, it's a hoot! What the hell was I worried about?! This is way
better than any damn fairground ride. I try the maneuver next. Again, that
vicious tip stall rears its head but in spite of my instruction to the contrary
I instinctively crank in opposite aileron. D'oh! I try it again and this
time I remember the rudder but I'm still trying to steer out of it with
the ailerons as well, though not quite as much and I straighten the wheel
right away. Another go - this time for sure! Well, maybe not. Again I stall
the plane and again I feed in both rudder and aileron to correct the wing
drop. Stupid brain. Well, I get the idea anyway, I'll just have to practice
it more in future. |
Tony finishes off the lesson with a demonstration of what we definitely
don't want to inadvertantly get into - a spin. This is the most violent
maneuver yet, but again, it's a hoot and not a sign of airsickness!! The
nose comes up and as the airplane stalls he kicks in full opposite rudder
with a bit of power to induce the tip stall. The airplane whips over and
next thing I know I'm looking straight down at the ground spiralling up
at me. After a couple of turns Tony stops the spin and we pull about 5g's
on the recovery from the dive. The Cessna 150/152 is notoriously difficult
to get into a spin and that was really more of a spiral dive so we give
it another go but again the old Cessna refuses to get into a true flat spin.
Ah well, I thoroughly enjoyed the experience anyway and I got out of the
airplane at Barton feeling on top of the world and with a great sense of
relief that my concerns had been for nothing. The lesson has given me more
confidence and a greater knowledge of just what I can and can't do with
the airplane. |
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